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Lecture 01: Introduction

Textbook:

The 68000 Microprocessor: Hardware and Software Principles and

Applications, by James Antonakos, 5th Edition, Prentice Hall, 2004.

Excerpted from lecture notes prepared by Jie Hu, Assistant Professor, Electrical and Computer EngineeringNewark College of EngineeringNew Jersey Institute of Technology

Topics

v Evolution of computers

v Microprocessor based systems

v Microprocessor operation

v Historic perspective: the Macintosh PC

v Programming languages

v Developing software for 68000 microprocessor

Evolution of Computers

v First generation (vacuum tubes), 1946-1958Ø features huge, slow, expensive, and undependable

Ø Examples: § ENIAC (Electronic Numerical Integrator and Computer), 1946

§ EDVAC (Electronic Discrete Variable Automatic Computer), 1947

§ UNIVAC I (UNIVersal Automatic Computer), 1951

v Second generation (transistor), 1959-1964Ø In 1947, John Bardeen, William Shockley, and Walter Brattain working

at AT&T's Bell Labs invented transistor

Ø Transistors conduct electricity faster and better than vacuum tubes, were also much smaller and gave off virtually no heat compared to vacuum tubes

v Third generation (integrated circuit), 1965-1970Ø Robert Noyce of Fairchild Corporation and Jack Kilby of Texas

Instruments independently discovered integrated circuits

v Fourth generation (LSI/VLSI, Microprocessor), 1971-presentØ By putting millions of transistors onto one single chip more calculation

and faster speeds could be reached by computers.

Evolution of Computers

v ENIAC (Electronic Numerical Integrator and Computer), 1946, UPenn

Fine-tuning ENIAC. J. Presper Eckert (the man in the foreground turning a knob) served and John Mauchly (center) designed ENIAC to calculate the trajectory of artillery shells. The machine didn't debut until February 1946, after the end of World War II, but it did launch the computer revolution.

Courtesy of the Computer History Museum.

Facts:5000 simple adds/subs per secondPower: 150KWWeight: 30 tonsSize: 1800 sq. ft (167 m2)

Contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints.

ENIAC Vacuum Tubes

Vacuum tubes act like an amplifier and a switch. Without any moving parts, vacuum tubes could take very weak signals and make the signal stronger (amplify it). Vacuum tubes could also stop and start the flow of electricity instantly (switch). These two properties made the ENIAC computer possible.

The First Transistor

v Modern-day electronics began with the invention in 1947 of the transfer resistor, also known as the bi-polar transistor by Bardeen et.al at Bell Laboratories

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The First Integrated Circuit (IC)

v In 1958 the integrated circuit was born when Jack Kilby at Texas Instruments successfully interconnected, by hand, several transistors, resistors and capacitors on a single substrate

2300 transistors13.5 mm2108k Hz

Intel 4004 Microprocessor (10000 nm) 1971

2nd Generation (32-bit) Motorola 68000

v Major architectural step in microprocessors:

Ø First 32-bit architecture

§ initial 16-bit implementation

Ø First flat 32-bit address

§ Support for paging

Ø General-purpose register architecture

§ Loosely based on PDP-11 minicomputer

v First implementation in 1979

Ø 68,000 transistors

Ø < 1 MIPS (Million Instructions Per Second)

v Used in

Ø Apple Mac

Ø Sun , Silicon Graphics, & Apollo workstations

IBM Power PC 970 (130nm) 2003

1.8 Ghz58 M118 mm2

Apple Power G5, the fastestPC in 2003, has dual PPC 970CPU

Sun Niagara I (Ultra SPARC T1)(90nm), 14 Nov. 2005

v 8 Processor Cores

v Each SMT core running 4 threads à total 32 threads

v Each core at 1.2GHz

v 300M transistors

v Die size: 380mm2

Intel Core2 Quad Processors (65nm), Jan. 2007

v 4 Cores on 2 separate dies on the same package

v 2.66GHz

v 291Mx2 transistors

v Die size: 143mm2x2

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Microprocessor based Systems

Parallel I/O Serial I/OInterruptCircuitry

CPUTiming Memory

System Bus

Microprocessor based Systems

v CPU (central processing unit)

Ø microprocessor

Ø logic circuitry for communicating with the system bus: data/address bus driver, bus controller

v Timing unit

Ø generates clock signals and is responsible for the proper operation of all system hardware

Ø crystal oscillator and timing circuitry

v Memory

Ø stores both program code and data

Ø ROM (read-only memory), RAM (random access memory)

v Interrupt circuitry

Ø mechanism for the processor to respond to special external events

v I/O, peripherals

Ø monitor, keyboard, mouse, printer, …

Microprocessor based Systems

Microprocessor, by-itself, completely useless – must have external peripherals to Interact with outside world

Microprocessor Vs Microcontroller

No matter what is the system size, the most important component

is still the processor

Microprocessor Operation

Reset

Fetch

Decode

Execute

Start here at power-on or when a reset signal is received

1.Output inst. address on address bus

2. Read inst. pattern from memory onto data bus

3. Increment inst. pointer (program counter)

Determine what type of instruction was fetched

1. If necessary, read data from memory

2. Execute instruction

3. if necessary, write results to memory

Repeat this process until power is turned off or the processor is halted.

Contin…

v Fetch cycle:

during it, processor loads an instruction from memory into its internal instruction register

v Decode cycle:

during it, microprocessor determines what type of instruction has been fetched

v Execute cycle:

may need to read more data from memory or write results to memory

v Also monitors other signals such as WAIT, HOLD, or READY inputs

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Macintosh PCs based on 68000

v Macintosh 512K introduced 1984 at $3300, discontinued 1986

v CPU: 8MHz 68000

v Performance: 0.7 MIPS(Million instruction

per second)

v ROM: 64KB

v RAM: 512KB, expandable to 4MB

v Display: 9” B&W screen, 512X342 pixels

v Keyboard, mouse

v Serial port: DB-9 modem and printer ports

v Floppy disk driver: floppy 400KB single side

*Most of the electronics were contained on motherboard.

Block Diagram of Macintosh 512K Motherboard

Processor68000

I/O Interface6522

Real-timeclock

Serial I/O8530

Floppy diskcontroller

SystemROM

RAM buffersand Mux

PALdecoders

DynamicRAM

512KB

Soundlogic

Videologic

SpeakerVideo

display

Control

signals

Modem PrinterMouse Keyboard

System bus

Disk drive

Program the Computer Systems

v Software manages hardware resources and instructs hardware how to perform a task

Ø Device drivers

Ø System software: operating systems

Ø Application software

v A general process for problem solving

ProblemData structures

& algorithmsfor solution

pseudo code

programming Programcode in HLL or Assembly

Machinecode

Run the codetranslatingload

Results

Compilation, Assembly, and Linking

HLL compiler assemblyassemblerHLLHLL assemblyassembly

code

linkerexecutableloader

assemblyassemblyobject

code

Programming Languages

v Natural languages: English, Chinese, French, …

Ø e.g., “please print out ‘Hello!’ on the display screen.”

v High-level programming languages: C/C++/C#, Java, Pascal, Fortran, …

§ Syntax of a high-level language is similar to English

§ A translator is required to translate the program written in a high-level language into object code -- done by a compiler.

§ There are cross compilers that run on one onecomputer but translate programs into machine instructions to be executed on a computer with a different instruction set.

§ Main drawback is slower execution speed of the machine code obtained after compiling an HLL program.

Programming Languages

§ However, C language has been extensively used in microcontroller programming in industry

v Assembly languages: 68000 assembly language, …Ø e.g.,

ORG $8000 ;starting address of data

HMSG DC.B ‘Hello!’ ;message characters

DC.B 0 ;end-of-message marker

ORG $8100 ;starting address of program

START MOVEA.L #HMSG,A3 ;load A3 with message address

TRAP #3 ;output message

TRAP #9 ;return to command processor

END START

main() {

printf(“%s”, “Hello!”);

}

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Programming Languages

§ An assembly program consists of assembly instructions§ An assembly instruction is a mnemonic representation of

a machine instruction e.g. MUL may stand for “multiply”§ Assembly programs must be translated into object code

before it can be executed -- translated by an assembler.§ Assemblers can be of two types: cross assembler and

native assembler.§ Cross assembler runs on one computer and generates

machine instructions that will be executed by another computer that has different instruction set, e.g.freeware ASM68K.

§ Native assembler runs and generates instructions for the same computer.

§ Drawbacks of assembly programs are:dependent on hardware organisation, difficult to understand long programs, low programmer productivity

Programming Languages

v Machine languages: recognized and executed by the hardware

Ø e.g.,

008000

008000 4865 6C6C 6F21

008006 00

008100

008100 267C 0000 8000

008106 4E43

008108 4E49

00810A

ORG $8000

HMSG DC.B ‘Hello!’

DC.B 0

ORG $8100

START MOVEA.L #HMSG,A3

TRAP #3

TRAP #9

END START

memory address

binary code shown in Hex

Hard to understand for human being

Jie Hu, ECE/NJIT, Fall 2008ECE252 L01-Introduction.27

Programming Tools for 68000

v EASy68K (preferred for this course)Ø EASy68K is a 68000 Structured Assembly Language IDE.

EASy68K allows you to edit, assemble and run 68000 programs on a Windows PC.

Ø download from http://www.monroeccc.edu/ckelly/EASy68K.htm

v or DOS based 68000 toolsØ com68k: 68000 C compiler (from the CD with the text book)

Ø asm68k: 68000 assembler

Ø emu68k: 68000 emulator

EASy68K Development System

v EASy68K includes

Ø Edit68K for editing and assembling 68000 assembly code

Ø and Sim68K for running 68000 programs

v Start Edit68K from Windows XPØ Start menu à All Programs à EASy68K à Edit68K

Edit 68000 Assembly Code in Edit68K

v First 68000 assembly program: Hello.X68

Assemble 68000 Code in Edit68K

v After save source code Hello.X68, click “Assemble Active Source” button to assemble the code

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Assemble 68000 Code in Edit68K

v After assembling, two more files will be created in the same directory of Hello.X68: Hello.L68 and Hello.S68

Simulating 68000 Code after Assembling

v Click “Execute” button in the Popup window to invoke Sim68K to run the code

Simulating 68000 Code after Assembling Check the Simulation Results